It is assumed that spatial reasoning about previously obtained information that describe relations between two or more objects is based on the construction and inspection of mental models. The paper mainly focuses on the question how humans integrate spatial information that initially appeared not to be linked. Two experiments investigated the construction processes of spatial mental models and the integration of additional information into existing models. The results show that combining information that are initially not related to one another takes longer and leads to more errors. Moreover, information presented in a continuous and a semi-continuous order was integrated sequentially, whereas information presented in a discontinuous order was first integrated sequentially into one temporary model and if necessary subsequently revised.